# Welcome to MentraOS Cloud

Welcome to the brain of MentraOS! If you're reading this, you're about to learn how smart glasses, mobile apps, and third-party applications all work together to create magical experiences for users.

## What is MentraOS?

MentraOS is an ecosystem that connects:
- **Smart Glasses** - Lightweight AR glasses with a display, camera, microphone, and sensors
- **Mobile App** - The user's phone that acts as a powerful compute bridge
- **Cloud Services** - That's us! We orchestrate everything
- **Third-party Apps** - External applications that extend functionality

Think of it like this: The glasses are your eyes and ears, the phone is your processor, the cloud is your traffic controller, and apps are your superpowers.

## The Journey We'll Follow

This documentation follows the journey of data through our system:

1. **Getting Connected** - How a user opens their app and connects their glasses
2. **Your Command Center** - The UserSession that manages everything for that user
3. **Speaking the Same Language** - The messages that flow between all the parts
4. **Building on MentraOS** - How apps plug into the system

## Key Concepts to Remember

### The Four Main Players

1. **Mobile App (Client)**
   - Authenticates the user
   - Manages Bluetooth connection to glasses
   - Connects to cloud via WebSocket
   - Sends glasses events to cloud

2. **Smart Glasses**
   - Captures audio, video, photos
   - Shows text on display
   - Sends sensor data (buttons, head position)
   - Limited processing power - relies on phone

3. **MentraOS Cloud (Us!)**
   - Manages user sessions
   - Routes messages between clients and apps
   - Handles transcription, translation
   - Enforces permissions and rate limits

4. **Third-party Apps**
   - Connect via our SDK
   - Subscribe to events they care about
   - Send content to display on glasses
   - Extend functionality (AI assistants, translators, etc.)

### The Basic Flow

Here's a simple example to get you oriented:

```
1. User speaks into glasses microphone
2. Audio streams through phone to cloud
3. Cloud transcribes the audio to text
4. Cloud sends transcript to subscribed apps
5. App processes transcript and sends back a response
6. Cloud sends response to glasses display
7. User sees the response on their glasses
```

## What Makes MentraOS Cloud Special?

- **Real-time Everything** - WebSockets for instant communication
- **Smart Session Management** - UserSessions that survive disconnections
- **Modular Managers** - Specialized components for audio, display, photos, etc.
- **Developer Friendly** - Simple SDK for building apps
- **Privacy First** - Users control what apps can access

## Ready to Dive In?

Let's start with [Authentication Flow](./2-authentication-flow.md) to see how users connect to the system.

Remember: The best way to understand MentraOS Cloud is to follow the data. Every action starts with a user, flows through our system, and results in something magical happening on their glasses.